Latest FC kernel still have SMP bugs?
Nigel Wade
nmw at ion.le.ac.uk
Thu Apr 1 16:30:48 UTC 2004
Mitch Wiedemann wrote:
> Is the FC1 2.4.22-1.2174.nptl kernel still having problems with SMP and
> hanging?
> I'm due to install some MP servers soon and want to avoid problems
> (imagine that!).
>
> If said kernel is still having trouble, what's the easiest fix?
>
> Thanks in advance.
>
I'm currently investigating SMP here. When I tried stock FC1 and the latest
2.4.22-1.2174.nptl I had severe problems with LDAP. I didn't get any hard
lockup, but I would have delays of between 4 and 300 secs in LDAP response
times. I have a strong suspicion that the delays are related to FUTEX, but
that's hard to prove.
I found that disabling hyperthreading is the answer to my problems. When I
disabled it in the BIOS LDAP started behaving itself.
I'm currently stress testing the LDAP server and it's managing ~40,000
requests per minute with the peak search times of around 5ms. I read in some
other threads that mounting/unmounting NFS and Samba filesystems lead to
hard lockups so I'm mounting/listing/unmounting one of each every half hour.
The test will be left running for the next 72 hours to see what happens...
--
Nigel Wade, System Administrator, Space Plasma Physics Group,
University of Leicester, Leicester, LE1 7RH, UK
E-mail : nmw at ion.le.ac.uk
Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555
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